Heretofore, in the precision mechanical industry, the optical instrument industry, the electrical and electronics industry and plastics industry, halogenated hydrocarbons have been known as solvents used for precision cleaning to remove soils such as oils, dusts, etc. attached to the surface of articles during manufacturing processes or the like.
However, since halogenated hydrocarbons such as chlorofluorocarbons or hydrochlorofluorocarbons have ozone depleting potential, researches to develop solvents that can substitute such halogenated hydrocarbons have recently been conducted, and hydrofluoroethers (hereinafter referred to as HFEs) are known as the solvents. HFEs have advantages such that they are inflammable, have excellent chemical and thermal stabilities, have excellent properties in drying, and have zero ozone depleting potential and low global warming potential. For example, HFE-7100 (C4F9OCH3, trade name of 3M) and HFE-7200 (C4F9OC2H5, trade name of 3M) are known as HFEs.
Generally, since HFEs have low solvency to oils as compared with the halogenated hydrocarbons, there has been a problem such that HFEs are difficult to be used as cleaning agents in place of the halogenated hydrocarbons.
However, the present inventors have found that (2,2,2-trifluoroethoxy)-1,1,2,2-tetrafluoroethane which is one of HFEs, can dissolve several oils, e.g. Panasate 810 (trade name of NOF CORPORATION).
However, in a case where an article to which Panasate 810 is attached is cleaned by using (2,2,2-trifluoroethoxy)-1,1,2,2-tetrafluoroethane, if the article is comprised of an acrylic resin or coated with an acrylic resin, there have been problems such that haze or cracking occurs on the surface of the article, and dissolution of the acrylic resin occurs.
On the other hand, Patent Document 1 discloses that an azeotrope-like composition comprising (2,2,2-trifluoroethoxy)-1,1,2,2-tetrafluoroethane and an alcohol such as methanol is useful as a removing agent for e.g. flux or oil, a cleaning agent for electronic components, resin-processed parts or optical lenses, or a dewatering/drying agent.
However, since the compositions disclosed in Patent Document 1 have significant effects on several resins such as an acrylic resin, there has been a problem such that in a case where an acrylic resin or an article coated with an acrylic resin is contacted with the compositions, haze, cracking or dissolution of the acrylic resin occurs.
Further, a perfluorocarbon such as perfluorohexane is also a compound having zero ozone depleting potential, but if it is used as a cleaning agent for e.g. oil, cleaning fails because its cleaning performance is insufficient.
Patent Document 1: JP-A-10-324897 (Scope of the Claims, paragraph 0009)